Improvement in pipe-wrenches



G. :1. CROSBY. PIPE-WRENCH.

Patented l'u'ne 27,1876.

N-PETERS, PNOTO-UTMOGRAPNER, WASHINGTON, D C,

UNITED STATES PATENT OFFICE.

GEORGE H. CROSBY, OF EAST SOMERVILLE, MASSACHUSETTS.

IMPROVEMENT IN PlPE-WRENCHES.

Specification forming part of Letters Patent No. 179.276. dated June 27,1876; application filed March 25, 1876.

To all whom it may concern.-

Be it known that- I, GEORGE E. CROSBY, of East Somerville,Massachusetts, have invented certain new and useful Improvements in PipeDogs or Wrenches, of which the following is a specification:

My improvements relate to the construction and arrangement of thehook-jaw of pipe (logs or wrenches, to means for adjusting it, and tothe manner of combining it with the dogjaw and lever or handle.

The nature of my inventlon, and the manner in which the same is or maybe carried into effect, can best be explained and understood byreference to the accompanying drawing, in which- Figure 1 is aperspective view of a pipe dog or wrench embodying my improvements. Fig.2 is a longitudinal central section of the same.

A is the hook-jaw, carried by and. adjustable in a center block, B,which is pivoted in theslotted extension or strap C, formed or providedwith a dog-jaw, D. To the strap or dog-jaw extension is secured theleveror handle E. The front or breast of the center block is convex, thecurvature being upon the are of a circle, of which the pivot to is thecenter. This portion of the block bears against a corresponding concaveface of the strap or extension C. The adjustment of the hook-jaw isprovided for in this instance by fitting its shank 0 into acorrespondingly-shaped socket in the center block, and by combining withthe block an adjusting-screw, d, which rotates in the block. and extendsinto and engages the hollow interiorly screw-threaded shank c. When thescrew, by means of its exterior head, is rotated, the hook-jaw will beraised or lowered, according to the direction of rotation of the screw.()n the shank of the hookjaw I form graduation-marks or a scale, asshown in Fig. 1, to facilitate the adjustment of the jaw for differentsizes of pipes, 850.

I prefer to make the hook-jaw of steel. The center block may be eitherwrought, cast, or malleable iron. The strap or extension should be ofmalleable cast-iron or cast-steel; and the nose-piece e of the dog-jaw,suitably fitted and fastened to the extension, should be tempered steel.The handle canbe either solid, cast, or wrought iron, or wrought-ironpipe screwed on or welded. In the drawing I have representedwrought-iron pipe screwed on.

The manner of using my improved pipe dog or wrench will be understoodwithout explanation.

The advantages due to my invention are many. Not so many different sizesof dogs, tongs, or wrenches for pipe are required as heretofore. Thewrench does not weigh so much as the usual adjustable tongs or wrenches,and is much more easily and perfectly adjusted to different sizes ofpipe. By the use of the center block the adjusting-screw is entirelycovered up and protected from all injury; and by the describedarrangement of parts the strain on the screw is such as to removeliability of its buckling or bending.

What I claim, and desire to secure by Letters Patent, is as follows:

1. The hook-jaw carried by and adjustable in the pivoted center block,substantially as set forth.

2. The combination of the pivoted center block, that carries theadjustable hook-jaw, with the strap or slotted dog-jaw extension,substantially as set forth.

3. In combination, the pivoted center block. the hook-jaw, with hollowshank fitting a socket in said block, and the adjusting-screw carried bysaid block, and engaging said shank, substantially as shown and setforth.

4. The dog-jaw, slotted dog-jaw extension, and handle, in combinationwith the pivoted center block, adjustable hookjaw, and adjusting-screw,these parts being arranged together for joint operation, substantiallyas specified.

In testimony whereof I have hereunto sign6ed my name this 23d day ofMarch, A. D. 187

GEORGE H. CROSBY.

Witnesses:

J. H. MILLETT, J OHN S. HOLMES.

